Alexandrite
Alexandrites are among the rarest, most spectacular and expensive gemstones in the world. The earliest important source of them was the Ural mountains of Russia. The gem became a favorite of the Russian royal family and was named after the Russian Czar, Alexander II. This gem is special mostly because of the enchanting way in which the color changes dramatically according to the light it is in. Alexandrite is a gemstone of the mineral chrysoberyl. In addition to the Ural Mountains (its most famous and definitive source), quality alexandrites are found in Brazil, and sometimes Sri Lanka, Myanmar (Burma), Tanzania and India. Most people will go there whole lives without ever seeing a natural alexandrite. What they will see instead, is man-made (synthetic) Alexandrite. Synthetic alexandrite comes in very large sizes with perfect color and dramatic color change. Whereas natural alexandrite can cost $10,000/carat or more, synthetic alexandrites are available for a few hundred dollars. Color-Change: The more dramatic and complete the change of color in an Alexandrite gemstone, the more valuable it is. Color change is often noted in the description or lab certificate of an alexandrite in terms of percentage, with 100% being the ideal. Learn more about how color change affects the value of alexandrite Color hues: Alexandrites, like so many gemstones range widely in available colors. The most desirable colors of alexandrite are bright, richly saturated and without tones of grey or brown. Reds and greens are the most expensive and sought after. Learn more about how color affects the value of alexandrite Size: Large alexandrites are very rare. Any quality natural alexandrite over 1 carat is hard to find, and more expensive than any diamond of similar quality. Clarity: As with all crystaline gemstones, the fewer internal imperfections, the more valuable the alexandrite gemstone. how clarity affects the value of alexandrite Cut: And again, a good cut is not as important inan alexandrite as it is in many other gemstones, but whenever present, a perfect cut will significantly increase the value of the gemstone. Read about how cut affects the value of alexandrite. Treatments, Synthetics and Imitations: Alexandrites are treated sometimes to improve their appearance. Because of their high price tag and beauty that everyone loves, they are also widely synthesized and imitated. An honest seller will clearly explain the difference, but sadly, many do not. Read here to learn about treatments, synthetics and imitations of alexandrite and how to tell the difference. Meaning and Symbology: Alexandrites are special gems, which, despite their relatively recent discovery already have a rich folklore and history. Learn more about alexandrite meaning and symbology to see if it”s something you relate to. Color Various shades of green, yellow, brownish to greenish black, may be raspberry-red under incandescent light when chromian; colorless, pale shades of yellow, green, or red in transmitted light Crystal habit Crystals tabular or short prismatic, prominently striated Crystal system Orthorhombic Twinning Contact and penetration twins common, often repeated forming rosette structures Cleavage Distinct on (110), imperfect on (010), poor on {001} Fracture Conchoidal to uneven Tenacity Brittle Mohs scale hardness 8.5 Luster Vitreous Streak White Specific gravity 3.5 - 3.84 Optical properties Biaxial (+) Refractive index nα=1.745 nβ=1.748 nγ=1.754 Pleochroism X = red; Y = yellow-orange; Z = emerald-green 2V angle Measured: 70° References 123 Major varieties Alexandrite Color change; green to red Cymophane Chatoyant